Ring is pure open source alternate to Skype under GPL v3 license, for those people who focused on security and Privacy Ring could be the best choice.
It comes with almost same feature as what Skype offers, Like Instant Messaging, Voice call, Video call and Conference.
It is cross platform tool, works on iOS, Linux, windows and Android. Currently its in beta version, Its good to download and give a try. Rush now to reserve your own username.
Why its better than WhatsApp, Telegram, you doesn’t need a mobile number to register an account, so you have are not tied into a mobile number.
Ring is developed and compliance with industry standard protocols, like SIP, DHT Kademlia, TLS, etc. Also Ring team committed to improve the product and long term support.
If you are willing to contribute in translation to your local language, you are invited to participate. https://ring.cx/en/contribute/translate